Title :
Modifications to repetitive-based controllers using FIR filters for practical implementation
Author :
Escobar, G. ; Mattavelli, P. ; Martinez-Montejano, M.F.
Author_Institution :
ABB Corp. Res. Center, Dattwil, Switzerland
Abstract :
In this paper some modifications are proposed for the practical implementation of repetitive-based schemes used to compensate harmonic distortion. In a practical implementation, the repetitive schemes required both, to limit the gain originally infinite, and to restrict the bandwidth (BW) of the controller originally of infinite dimension. In general terms, each delay line in the repetitive scheme has an associated limiting gain and a low pass filter (LPF). However, it has been observed that this practical modifications can produce a considerable phase shift at the frequencies of interest. As a consequence, the compensation of harmonics cannot be guaranteed anymore. One possibility to compensate such a phase shift consists in the modification of the delay time in the delay line of the repetitive scheme. However, in the case of conventional LPFs, the phase shift is usually a nonlinear function of the frequency, which makes this task very difficult. To overcome this issue, this paper proposes the use of low pass FIR filters, whose phase shift can be made linear by following appropriate design rules. Notice that a low pass FIR filters with a linear phase shift produces a constant delay time, which is much easier to compensate. Numerical results are provided to illustrate the benefits of the modified schemes.
Keywords :
FIR filters; delay systems; harmonic distortion; linear phase filters; low-pass filters; nonlinear functions; power system control; power system harmonics; FIR filter; delay line; delay time; harmonic distortion; harmonics compensation; limiting gain; linear phase shift; low pass filter; nonlinear function; repetitive-based controller; Adaptive systems; Electric variables control; Finite impulse response filter; Induction motors; Machine vector control; Magnetic flux; Mechanical sensors; Rotors; Sensorless control; Torque control;
Conference_Titel :
Industrial Electronics, 2009. IECON '09. 35th Annual Conference of IEEE
Conference_Location :
Porto
Print_ISBN :
978-1-4244-4648-3
Electronic_ISBN :
1553-572X
DOI :
10.1109/IECON.2009.5415209